1. Field of the Invention
The present invention relates to a substrate processing system and a substrate processing method for performing a sequence of processes for various types of substrates such as semiconductor wafers and liquid crystal display (LCD) glass substrates.
2. Description of the Related Art
In fabrication processes for LCD substrates and semiconductor devices, fine circuit patterns are formed using a photolithography technology. In the photolithography technology, a resist is coated in a film shape on the front surface of a raw substrate such as an LCD substrate or a semiconductor wafer and then exposed with a predetermined pattern. After the exposed pattern is developed and etched, a desired circuit pattern is obtained.
Recently, as the sizes of semiconductor wafers are becoming large, in the photolithography process, wafers are successively processed. For example, in a complex processing system that performs both of a resist coating process and a developing process, wafers are extracted from a cassette one by one. The extracted wafers are processed in a processing unit one by one. The processed wafers are returned to a cassette. such a complex processing system, one cassette contains for example 25 unprocessed wafers. The wafers are extracted from the cassette one by one. The extracted wafers are successively processed in individual processing units. The processed wafers are returned one by one to an empty cassette. Wafers that are extracted from one cassette and processed in individual processing units are referred to as one lot.
In such a conventional processing system, cassettes are accessed to a processing portion with the stages of four holding tables that hold the cassettes. Assuming that a portion that holds a cassette containing unprocessed wafers and a portion that holds a cassette containing processed wafers are required, one lot uses two stages. Thus, the system has only two stages that hold cassettes containing unprocessed wafers.
Thus, in such a system, to successively process lots, after a first lot has been processed, until a second lot is processed, the operator should change a cassette that contains processed wafers with a cassette that contain unprocessed wafers. However, when the operator repeats such an operation, he or she tends to confuse which cassette contains processed wafers. In addition, the operator cannot know when one lot is processed. Thus, while substrates are being processed, the operator should always watch the operation of the system so that he or she can properly change cassettes. If the operator forgets to change cassettes, the system does not properly operates, thereby remarkably decreasing the throughput of the system.
An object of the present invention is to provide a substrate processing system and a substrate processing method that allows the throughput of the system to improve.
According to the first aspect of the present invention, the present invention is a substrate processing system that successively extracts unprocessed wafers from a cassette, and successively conveying the extracted wafers to a plurality of processing units to be processed and returning the substrates that completed all the process successively to the cassette. The present invention is comprising of a loading/unloading portion for loading a cassette that contains a plurality of unprocessed substrates corresponding to one lot and unloading a cassette that contains a plurality of processed substrates corresponding to one lot, a processing portion having a plurality of processing units for performing a plurality of processes for substrates, a conveying portion, disposed in the processing portion, for exchanging substrates with the loading/unloading portion and successively conveying the substrates to the processing units, a process procedure setting portion for setting process procedures containing process conditions for individual lots, a calculation processing portion for calculating a process completion prediction time for predicting a process timing for one lot, and an informing portion for informing the operator of the process completion prediction time calculated by the calculation processing portion.
A recipe as a process procedure contains at least information that designates a processing unit. More preferably, such a recipe contains a process procedure such as real process times of individual processing units and process conditions thereof.
In such a manner, the process completion prediction time is calculated and the operator is informed thereof corresponding to the designated recipe. Thus, the operator can change a cassette corresponding to the process completion prediction time.
The informing portion preferably has a displaying portion for displaying a screen for the process completion prediction time. The displaying portion is for example an LCD panel. Since the process completion prediction time is displayed, the operator can properly change a cassette corresponding to information that is displayed.
The calculation processing portion preferably has a storing portion. The calculation processing portion calculates the process completion prediction time corresponding to old process procedures and completion times thereof stored in the storing portion. Thus, the calculation processing portion can properly calculate the process completion prediction time.
The substrate processing system further comprises a temperature and humidity detecting portion for measuring the temperature and humidity in the processing portion, and a controlling portion for adjusting the temperature and humidity in the processing portion corresponding to an output of the temperature and humidity detecting portion and determining whether or not the temperature and humidity are in predetermined ranges. Thus, the system can start real processes in the state that the temperature and humidity are stable in the processing portion. The processing units of the processing portion preferably include a heat processing unit, and a solution processing unit which has the temperature and humidity detecting portion. Thus, since the temperature and humidity of the solution processing units should be accurately managed, after the temperature and humidity thereof become stable, the real processes can be performed.
In addition, the process completion prediction time includes at least one of a first process completion prediction time at which the first unprocessed substrate of one lot is returned to the loading/unloading portion after the substrate is conveyed to a processing unit, a second process completion prediction time at which all unprocessed wafers of one lot are conveyed to a processing unit after the first unprocessed wafer of the lot is conveyed to the processing unit, and a third process completion prediction time at which all processed wafers of one lot are returned from a processing unit to the loading/unloading portion after the first unprocessed wafer of the same lot is conveyed to the processing unit.
The calculation processing portion preferably calculates a cassette changeable time period for which a cassette that contains unprocessed substrates can be changed corresponding to the second process completion prediction time. Thus, since as information that is more detail than the process completion prediction time, a time at which a cassette that contains unprocessed substrates can be obtained. Thus, the operator can more effectively change a cassette that contains unprocessed substrates. Alternatively, the calculation processing portion calculates the cassette changeable time period for which a processed wafer cassette CR can be changed corresponding to the first and third process completion prediction times. Thus, as information that is more detail than the process completion prediction time, a time at which a cassette that contains processed wafers can be obtained. Thus, the operator can more effectively change a cassette that contains processed cassettes.
The calculation processing portion preferably has a storing portion for storing the elapsed time after the cassette changeable time period until the cassette change completion prediction time. Thus, even if the operator forgot to change a cassette, the process completion prediction time and the cassette changeable time can be re-calculated in consideration of the elapsed time of the process completion prediction time.
A second aspect of the present invention is a substrate processing method for successively extracting unprocessed substrates from a cassette, successively conveying the extracted wafers to a plurality of processing units, causing the processing units to process the conveyed substrates, and successively returning the processed substrates to a cassette, the method comprising the steps of calculating a process completion prediction time for predicting a process timing for each lot corresponding to a process procedure including process conditions for at least one lot, informing the operator of the process completion prediction time, accepting a cassette that contains a plurality of unprocessed substrate for one lot corresponding to the informed process completion prediction time, and returning a cassette that contains a plurality of processed substrates for one lot.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.